Event Number 2774

Abstract: An unresolved problem in the Standard Model is the observed presence
of matter and lack of corresponding antimatter in the universe. To
explain the matter-antimatter asymmetry, Sakharov suggested three
conditions had to be met: that baryon number is violated, CP violation
and that matter and antimatter are out of thermal equilibrium. A
sufficient source of CP violation could be from new physics in the
quark sector, or in the lepton sector within neutrino mixing.

The conversion of muon neutrinos to electron neutrinos, nue
appearance, is sensitive to CP violation between the light neutrinos,
which can be related to CP violation of a hypothetical heavy neutrino
in the early universe to meet Sakharov's conditions. However, nue
appearance is also dependant on precision measurements of other mixing
parameters, including Dm2(32), theta(23) and theta(13). The
Tokai-To-Kamioka (T2K) long baseline neutrino experiment is designed
to precisely measure muon neutrino disappearance (Dm2(32), theta(23))
and nue appearance. The experiment uses a beam of muon neutrinos
generated at the J-PARC facility in Tokai-mura, Japan, which is
sampled by two near detectors, ND280 and INGRID, before reaching the
Super-Kamiokande detector, 295km away. Since the March 2011
earthquake, T2K has recovered, resumed and updated the nue appearance
analysis with an increased data set corresponding to 3.01e20 protons
on target (at 15.5 kW x 10^7 s). This seminar will highlight T2K's
incredible recovery and analysis improvements, and discuss prospects
for future neutrino-based searches for CP violation in the lepton
sector.